Dec. 16: Federal prosecutors, seeking to build a case against WikiLeaks founder Julian Assange for his role in a huge dissemination of classified government documents, are looking for evidence of any collusion in his early contacts with an Army intelligence analyst suspected of leaking the information. Justice department officials are trying to find out whether Mr Assange encouraged or even helped the analyst, Pfc. Bradley Manning, to extract classified military and state department files from a government computer system.

If he did so, they believe they could charge him as a conspirator in the leak, not just as a passive recipient of the documents who then published them. Among materials prosecutors are studying is an online chat log in which Private Manning is said to claim that he had been directly communicating with Mr Assange using an encrypted Internet conferencing service as the soldier was downloading government files. Private Manning is also said to have claimed that Mr Assange gave him access to a dedicated server for uploading some of them to WikiLeaks.

Adrian Lamo, an ex-hacker in whom Private Manning confided and who eventually turned him in, said Private Manning detailed those interactions in instant-message conversations with him. He said the special se-rver’s purpose was to allow Private Manning’s submissions to “be bumped to the top of the queue for review.” By Mr Lamo’s account, Private Manning bragged about this “as evidence of his status as the high-profile source for WikiLeaks.”

Wired magazine has published excerpts from logs of online chats between Mr Lamo and Private Manning. But the sections in which Private Manning is said to detail contacts with Mr Assange are not among them. Mr Lamo described them from memory in an interview with the Times, but he said he could not provide the full chat transcript because the FBI had taken his hard drive, on which it was saved. Since WikiLeaks began making public large caches of classified government documents this year, justice department officials have been struggling to co-me up with a way to charge Mr Assange with a crime.

Among other things, they have studied several statutes that criminalise the dissemination of restricted information under certain circumstances, including the Espionage Act of 1917 and the Computer Fraud and Abuse Act of 1986. But while prosecutors have used such laws to go after leakers and hackers, they have never successfully prosecuted recipients of leaked information for passing it on to others — an activity that can fall under the First Amendment’s strong protections of speech and press freedoms.

Last week, Attorney-General Eric H. Holder Jr said he had just authorised investigators to take “significant” steps, declining to specify them. This week, one of Mr Assange’s lawyers in Britain said they had “heard from Swedish authorities there has been a secretly impaneled grand jury” in Virginia. Justice department officials have declined to discuss any grand jury activity. But people familiar with the case said the department appeared to be attracted to the possibility of prosecuting Mr Assange as a co-conspirator to the leaking because it is under intense pressure to make an example of him as a deterrent to further mass leaking of electronic documents over the Internet.